California Audio Laboratories Aria Mk.III CD player Measurements

Sidebar 2: Measurements

I checked the AC voltage from chassis ground to main (house) ground on the player to determine the correct line-cord orientation. The Aria III, with its three-prong connector, measured about 12V, though this voltage will be shunted to ground when the player is connected to a properly grounded preamplifier.

In order to determine the cause of the slight tracking problems encountered with the Aria, I checked it with the dropout tests on the Pierre Verany Digital Test CD. The results were perhaps indicative of the problem but not necessarily conclusive: the Aria III mistracked on the 2mm gap. The CD standard only requires tracking of a 0.2mm gap, although theoretically the error-correction codes make regeneration of gaps of up to 2.47mm possible.

The Aria's output was non-inverting. The measured frequency response of the Aria III (fig.1) shows a noticeable droop at the extreme high end. While –2dB at 20kHz would be a trivial deviation in a phono cartridge, it is atypical of a CD player and may be responsible for the very slight loss of top-end "air" noted in the auditioning. The de-emphasis error (fig.2) has an abrupt peak at 10kHz (though not a large one—note the scale) which will slightly brighten pre-emphasized discs. The channel separation, shown in fig.3, was greater than 85dB at 200Hz, decreasing to 75dB at 1kHz and 55dB at 10kHz, indicating possible capacitive coupling between the channels, perhaps due to adjacent circuit board tracks.

Fig.1 CAL Aria 3, frequency response at –12dBFS (right channel dashed, 0.5dB/vertical div.).

Fig.2 CAL Aria 3, de-emphasis error (right channel dashed, 0.5dB/vertical div.).

Fig.3 CAL Aria 3, channel separation.

The spectral analysis of a –90.31dB dithered 1kHz sinewave (fig.4) shows a considerable amount of power-supply–related noise (of several harmonics), though all of it below –90dB—and none of it audible during any of the auditioning. (While several of the harmonics are nearly as high in level as the –90dB test signal, they will be much less audible because of the ear's decreased sensitivity at low frequencies.) Note the relative absence of signal harmonics, indicating relatively good DAC alignment.

Fig.4 CAL Aria 3, spectrum of dithered 1kHz tone at –90.31dBFS, with noise and spuriae (16-bit data, right channel dashed).

The Aria III's linearity at low levels is shown in fig.5 (only the right channel is shown—the left channel was just marginally better). While this is a good result, it is not up to the very best available from today's technology. But the CAL's IM distortion measurement (fig.6) is outstanding. The two test signals at 19 and 20kHz are clearly visible, with very little else to comment on, apart from the very slight intermodulation spurs at 18 and 21kHz. The squarewave result (fig.7) shows a slight rounding of the leading edge (from the HF rolloff) with the clipped Gibb's phenomenon ringing typical of the digital filter used. And though the –90dB undithered tone has a good waveform (fig.8), it shows a slight downward slope from left to right indicative of the already-noted power-supply hum.

Fig.5 CAL Aria 3, right-channel departure from linearity (2dB/vertical div.).

Fig.6 CAL Aria 3, HF intermodulation spectrum, DC–22kHz, 19+20kHz at 0dBFS (linear frequency scale, 20dB/vertical div.).

Fig.7 CAL Aria 3, 1kHz squarewave.

Fig.8 CAL Aria 3, waveform of undithered 1kHz sinewave at –90.31dBFS (16-bit data).

The Aria III's output impedance measured 52.8 ohms. Overall, its measured performance was respectable, though still in the mid-rank, objectively speaking, of the present players.—Thomas J. Norton